Winter riding and keeping battery warm

I'm looking to do a bit of winter riding. Obviously at below freeing temps, so my main concern is the risk to a lipoly cells I use. From what I've gathered and from the recommendations and warnings on the Dewalt drill I own, below certain temps there are risks of permanent damage to the battery; decreased and unrecoverable capacity loss.

Anyone have any means of keeping the batteries shielded and maybe slightly warmed to around 60F?

I was thinking of trying to use some insulated/electric heated glove inserts or car seat warmers in some sort of re purposed fashion. Perhaps with some rheostat or resistors to control the power.

Any suggestions or ideas? Thanks!

12-C said:

Any suggestions or ideas? Thanks!

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A few have been discussed, if it helps. This is just one possible search term set, and is only by topic title, so it's pretty restrictive. There's more out there.
https://endless-sphere.com/forums/search.php?keywords=batt*+warm*&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

https://endless-sphere.com/forums/viewtopic.php?f=14&t=23893epths
Dont let the title LiPo fool you, its to do with LiPo and other Lithium Ion batteries. Great info in there.

I posted in an old thread because it was interesting to read about cold weather and batteries and would like extra comments on it. I had a battery I kept outside for an hour or two maybe three, and it was bitterly cold. Battery was zip tied to rear rack, but thinking back on it I should have had it removable so I can take it inside with me.

Start out with the pack at room temp, and it won't freeze while you ride. It may get cold and put out less that ride, but that can be fixed with insulation, even just temporary stuff like wrap a towel around it for that ride.

I keep my winter ebike indoors .
Start riding with battery at room temperature.
while you draw power from batt. , it warms a bit depends on current.
I dont need isolate my pack from cold, but my winter trips are shorter .

bring your battery in with you might be an option.

I have a thin layer of insulation around my battery pack inside the hard-case, and it seems to keep the temperature quite well while in use. I tested it a couple of weeks ago when it was -9c outside. Starting temp was around +18c, and after a 35 minute ride the battery temp had only dropped around 2c.


The main danger when it comes to permanent battery damage is not low temp discharge, but low temp charging.
Charing below 0c will cause permanent damage instantly, and charging at high rate during less then 15c will cause excessive wear, so make sure battery is well warmed up before charing.
You can normally discharge at less then 0c at a reduced rate without causing damage, but if you start at room temp you'll cause less wear, have less voltage sag, and likely get more Wh out of the battery.